Motor fuel composition



United States Patent 6 3,502,451 MOTOR FUEL COMPOSITION Fred W. Mooreand Bruce S. Bailey, Fishkill, N.Y., as-

signors to Texaco Inc., New York, N.Y., a corporation of Delaware NDrawing. Filed Apr. 29, 1966, Ser. No. 546,212

Int. Cl. C101 1/10 US. Cl. 44-58 14 Claims ABSTRACT OF THE DISCLOSUREThis invention relates to a motor fuel composition for a four-cycle,spark-ignited internal combustion engine. More particularly, theinvention relates to a motor fuel composition containing polymers andtheir derivatives as additives in an amount effective to reduce oreliminate harmful deposits on the intake valves and around the ports ofan internal combustion engine; The invention also relates to a methodfor inhibiting the formation of such deposits.

Internal combustion engines of current manufacture are subject to asubstantial build-up of tenacious deposits on the intake valves andaround the ports of the engines. This condition is particularly true ofoverhead valve engines. The deposits seriously interfere with the properfunctioning of the fuel intake system. When their level has built up,the engine will exhibit substantial loss of power, rough idling and evenvalve burning. On further deposit build-up, portions will break off tobe drawn into the combustion chamber where they can cause furthermechanical damage to the engine.

Considerable work has been conducted to determine the-nature and causeof these deposits. The deposits are composed of the by-products of fuelcombustion and lubricating oil deterioration. Research has shown thatthe viscosity index improvers contained in the lubricating oil act asbinders for the deposits and that certain types of VI improvers appearto be worse than others. Polymethacrylate viscosity index improvers areone class of materials which appear to contribute materially to thedeposit build-up.

An understanding of engine operation will show how lubricating oildeterioration can contribute to deposits in theintake manifold. Aspark-ignited internal combustion engine contains a reservoir oflubricating oil in the crankcase. When the engine is running, thegreater part of the crankcase oil is splashed up on the operating partsof the engine and on the cylinder walls. A portion of this oil, however,is pumped to the upper parts of the engine to lubricate the workingparts therein. In an overhead valve engine, a small stream of the oilpumped to the upper section of the engine is constantly run over boththe intake and exhaust valve stems to insure that they are constantlylubricated in their guides during opera- Hce under the temperaturesexperienced resulting in the laydown and build-up of deposits with theviscosity index improver acting as a binder.

This particular problem is not encountered to any material extent in theexhaust manifold or around the exhaust valves. This is due in part tothe fact that there is less oil on the exhaust valves and possibly tothe high temperatures existing in the exhaust manifold which either donot permit the laydown of deposits or continually burn off any suchdeposits that may be laid down.

It has now been discovered that a minor amount of certain polyolefinpolymers and their corresponding hydrogenated derivatives dissolved in amotor fuel composition is effective for removing or preventing theformation of deposits on the intake valves and ports of a four-cycle,spark-ignited, internal combustion engine. More specifically, a motorfuel composition comprising a mixture of hydrocarbons boiling in thegasoline boiling range containing from about 0.01 to 0.20 percent of a Cto C polyolefin polymer or hydrogenated polymer having an averagemolecular weight in the range from about 500 to 3500 as determined by anosmometer is effective for removing the aforesaid deposits.

The polyolefin polymers which are employed in the motor fuel of theinvention are polymers prepared from monoolefins and diolefins orcopolymers of either having an average molecular weight in the range ofabout 500 to 3500. Mixtures of olefin polymers with an average molecularweight falling Within the foregoing range are also effective. Olefinswhich can be employed to prepare the polyolefin polymers includeethylene, propylene, butylene, isobutylene, amylene, hexylene, butadieneand isoprene. In general, the olefin monomers from which the polyolefinsare prepared are unsaturated hydrocarbons having from two to six carbonatoms. The polyolefin polymers from propylene and butylene areparticularly preferred for the practice of this invention. Otherpolyolefins which can be employed are those prepared by crackingpolyolefin polymers or copolymers of high molecular Weight to a polymerin the above-noted molecular Weight range. Derivatives of the notedpolymers obtained by saturating the polymers by hydrogenation are alsoeffective and are a part of this invention. The word polymers isintended to include the polyolefin polymers and their correspondinghydrogenated derivatives.

The base fuel of the invention comprises a mixture of hydrocarbonsboiling in the gasoline boiling range. This base fuel may consist ofstraight chain or branched chain paraffins, cycloparaffins, olefins andaromatic hydrocarbons or any mixture of these. This fuel can be derivedfrom straight run naphtha, polymer gasoline, natural gasoline or fromcatalytically cracked or thermally cracked hydrocarbons andcatalytically reformed stocks. The composition of the base fuel is notcritical nor does the octane level of the base fuel have any materialeffect on the invention. Any conventional motor fuel base may beemployed in the practice of this invention. The base fuel may containany of the additives normally employed in a motor fuel. For example, thebase fuel may contain an anti-knock compound, such as a tetraalkyl leadcompound including tetraethyl lead, tetramethyl lead, tetrabutyl lead,mixtures thereof and the like. The tetraethyl lead mixture commerciallyavailable for automotive use contains an ethylene chloride-ethylenebromide mixture 3 4 18 a scavenger for removing lead from the combustionbegun. The engine is operated on a four-stage-six-hour :hamber in theform of a volatile lead halide. The motor cycle for a total of 16 cyclesor 96 hours as follows:

Fuel may also contain any of the conventional anti-icing additives,corrosion inhibitors, dyes, upper cylinder Cycle Time Hours Operation,ubricating oils and the like. 1 5 (H 1 Idle The novel fuel compositionsof the invention are pre- 1-4 a Road load. pared by mixing a suitableamount of the prescribed polyggg f ner or polymer derived additive tothe base gasoline.

The amount of additive employed in the fuel composition s critical inorder to realize the benefits of the invention. 10 v Road Heavy 3roadly,the additive must be employed in a range from Operatim Idle Stage loadStage 108d Stage lbOllt 0.01 to 0.20 volume percent. Highly effectivere- Speed, 1.p,m 1000 225055 2250545 iults have been realized when theadditive amounts to k fig gf-gg 1L 5 315;: 5%; ).05 to 0.15 volumepercent of the fuel composition. The Spark Advance, B'I DC 1 a0 0 40 3gpreferred concentrat1on of the add1t1ve is an amount from 15 fif gi gfigf gi i f gi 3'; 23 Mod-:2 about 0.06 to 0.12 volume percent.Jacket-out templ, F- 200i2 200=i;2 200:1:2 The molecular weight of thepolymer or polymer deokcs 235*2 rivative is also critical in preparingan effective fuel com- 2 Typical Values, not controlled. 0 TDC t 600position according to this invention. Effective fuel com- Appmximatevalues'spark advance M6 B a positions of the invention require a polymeror hydro- Upon c0rnplet1on of a run, the cylinder heads and genatedpolymer derivative having an average molecular valves are removed andthe valves visually rated for the weight in the range of 500 to 3500 asdetermined by an extent of deposit build-up on the valve tulip surface.The )srnometer method. Highly eflective fu l compositions intake valvedeposits are rated according to a merit ratire obtained with polymersand derivatives having molec- 8 Scale running from 10 t0 The rating 10is P ilar weights in the preferred range from 650 to 2600. 25 fectly616311 Valve- The rating 1 is pp to an extremely Very effective fuelcompositions can be prepared from ily Coated V ve- Deposits arou d theport Openi g relatively low molecular weight polymers, that is using arerated g Mmedium and ypolymers having molecular weights in the range of500 The Buick Chassis Dynamometer Test is conducted us- ;0 995. ing a1964 Buick Wildcat car having a 425 CID V-8 en- Two tests were employedfor e l ti h d i i gine. All runs are made at 70 m.p.h. level roadcondilibiting effect of the novel fuels of the invention. One tiOIlSusing a run duration of 56 hours (3920 The Lest is the Buick ChassisDynamometer Test using a Buick overhaul of the engine and flushOperations are identical Wildcat automobile, The e ond t t i h B i k I dto the procedure described above for the Buick Induction Lion SystemDeposits Test conducted using a 1964 Buick System Deposits Test- Theintake valves and ports are 425 CID V-8 engine. The performance of th tt is rated using the same merit rating scale from the above pased on theratings of the intake valve and port deposits. test- The Buick InductionSystem Deposits Test is conducted TWO base fuels were employed in thefollowing examlsing as a test engine, a 1964 Buick 425 cu) V-H en- PBase Fuel A was a typical premium grade gasoline gine equipped i h a pcv(positive crankcase v containing 3 cc. of TEL per gallon. This fuelconsisted of :ion) valve and installed on a dynamometer test stand 27Percent aromatics, Percent Okfills and 5 P i h Supporting equipment tocontrol speed load and c ent saturated hydrocarbons as determined by FIAanalygine temperatures This test requires app i t l 350 S15. ThlS fuelhad an distillation I.B.P. Of 87 F., gallons of fuel and 4 gallons oflubricant for each run. an of and a research Octane number of Prior toeach run, the cylinder heads are completely reconditioned and new intakevalves installed. Special care 40 Base ,Fuel B was the Same as Base P Aexcept that nust be taken to assure that the inlet valve-to-valve guidei i i vqlume Rel-cent of a mixture of corro' :learance be maintainedbetween 0.0035 to 0.0045 inch. slon mhlbltor m mmfiral [n addition, thevalve seat widths are maintained between $1 2; figgg i igf i sgi if gfil t and & inch. The engine block is completely overy 1 v6 g valvedeposits ratings of 5.9 to 6.1. An improvement in 323F 13? lj g f Wlth gStated,m the rating to 6.4 is a significant improvement in the depositservlce maflua w m ow'by 011 rating and an improvement to 7.0 or above isa very sub- ;l1mpt1011 bGCOIIlC eXceSSlVe. stantial improvement TheeIlglIle 1S chafged Wlth four quarts f Oil f The examples in Table Igive the results of fuel comillslled 15 mlnutes at 1500 -P- Followlng an011 positions tested in the Buick Induction System Deposits irain, fourquarts of new oil are added and the fuel tests Test.

TABLE I.INDUCIION SYSTEMS DEPOSITS TEST Base Fuel B, Concentration Basefuel A, Concentration 0. 05% 0.075% 0. 10% 0. 10% Additive, Valve PortValve Port Valve Port Valve Port Valve Port Valve P ort mol. wgt. RatingRating Rating Rating Rating Rating Rating Rating Rating Rating RatingRating Runs 1-4, polypropene, 800 6. 4 Runs 5-7, polypropene, 975.." 7.6

Run 8, polypropene, 1,120 Runt polypropene, 897 1 r Runs 10, 11,polypropene, 1,150

Run 12, polypropene, 1,370-.. Run 13, polypropene, 2,560 Run 14,polybutene, 300 Run 15, polybutene, 730 5 Runs 16, 18, polybutene, 1,1008.7

Run 19, polybutene, 1,900 9 3 M Run 20, hydrogenated i i u polybutene,1,100 M-H Run 21, polybutene-1,800 7.8 L Run 22, 1 to 1 03-04 copolymer,1,010 8. 2 L

Run 23. C2-C4 ethylenebutylene copolymer, 810 30ntrol, no additive 5. 9H

The outstanding effectiveness of gasolines containing polyolefins andhydrogenated polyolefins within the prescribed concentrations andmolecular weight ranges is demonstrated. The ineffectiveness of motorfuels containing low molecular weight polybutene is also demon-'strated.

The examples in Table H show the results of fuel compositions of theinvention in the Chassis Dynamometer Test.

TABLE II.CHASSIS DYNAMOMETER TEST Base tuel B, concentration Valve PortValve Port Valve Port Additive, mol. wt. Rating Rating Rating RatingRating Rating Run 24, polypropene, 1120 7. 8 T-L Runs 25, 26,polypropene, 1150-.- 7. 8 M 7. 9 L Run 27, polybutene, 1100 7. 1 H

Run 28, blend of 0.0375% 800 M.W.

polypropene and 0.0375% 1,370M W. polypropene, 1,08

Control (no addit The outstanding effectiveness of the fuel compositionsof this invention are shown by the high valve rating in this test.

Polymers have previously been added to gasoline in amounts and molecularweight ranges elfective to thicken the gasoline and reduce its flowthrough the carburetor. Thus, Howard, US. 2,049,062, disclosesincreasing the kinematic viscosity of gasoline by 4 percent by addingpolymers of molecular weights from 2,000 to 270,000. The kinematicviscosity of the base fuel is not materially increased by the additionof the polymer derived additive in preparing the novel fuel compositionof this in vention. An amount of polymer which increases the viscosityof the base fuel by less than 1 percent is substanially ineffective forthickening the motor fuel composition.

Viscosity determinations were taken of the two base fuels and the novelfuels of the invention prepared from these base fuels. Kinematicviscosity in Stokes was determined at ditferent temperatures for thebase fuels described above and for the novel fuel compositions of theinvention prepared from these base fuels.

TABLE III.-EFFECT OF 800 MOLECULAR WEIGHT POLY- PROPYLENE POLYMER ONGASOLINE VISCOSITY Base Fuel B Base Fuel B+0.05% 800 M.W. polypropylene.Base Fuel B+0.075% 800 M.W. polypropylene Base Fuel B+0.1%

M.W. polypropylene Base Fuel B+0.2% M.W. p

g olypropylene.

The foregoing examples show that there is no increase in viscosity insome cases and where there is a small increase in viscosity it issubstantially less than 1 percent and generally less than 0.5 percent.

Obviously, many modifications and variations of the invention may bemade without departing from the spirit and scope thereof, and thereforeonly such limitations should be imposed as are indicated in the appendedclaims.

We claim:

1. A motor fuel composition comprising (A) a hydrocarbon base fuelconsisting of a mixture of hydrocarbons in the gasoline boiling rangeand (B) from about 0.01 to 0.20 volume percent based on said compositionof 1) a polymer of a C to C unsaturated hydrocarbon, (2) a 3. A motorfuel according to claim 1 in which said unsaturated hydrocarbon isselected from the group consisting of ethylene, propylene, isobutylene,amylene, hexylene, isoprene and butadiene.

4. A motor fuel according to claim 1 containing from about 0.05 to 0.15percent of said polymer or copolymer.

5. A motor fuel according to claim 1 containing from about 0.05 to 0.15percent of polypropylene havin a molecular weight in the range of 650 to2,600.

6. A motor fuel according to claim 1 containing a copolymer of C to Colefins having a molecular weight in the range of 650 to 2,600.

7. A motor fuel according to claim 1 containing from about 0.05 to 0.15percent of polypropene having a molecular weight of about 975.

8. A motor fuel according to claim 1 containing from about 0.05 to 0.15percent of polypropene having a molecular weight of about 800.

9. A motor fuel according to claim 1 containing polybutene-l having amolecular weight of about 800.

10. A method for preventing the build-up of intake valve and portdeposits in a spark-ignited, internal combustion gasoline engine whichcomprises supplying to said engine a motor fuel composition comprising(A) a hydrocarbon base fuel consisting of a mixture of hydrocarbons inthe gasoline boiling range and (B) from about 0.01 to 0.20 volumepercent based on said composition of (1) a polymer of a C to Cunsaturated hydrocarbon, (2) a copolymer of a C to C unsaturatedhydrocarbon, or (3) the corresponding hydrogenated polymer or copolymer,said polymer or copolymer having a molecular weight in the range fromabout 500 to 3,500.

11. A method according to claim 10 in which said polymer or copolymerhas a molecular weight in the range of 650 to 2,600.

12. A method according to claim 10 in which said unsaturated hydrocarbonis selected from the group consisting of ethylene, propylene,isobutylene, amylene, hexyl ene, isoprene and .butadiene.

13. A method according to claim 10 in which said gasoline fuel containsfrom about 0.05 to 0.15 percent of polypropylene having a molecularweight of about 14. A method according to claim 10 in which saidgasoline fuel contains from about 0.05 to 0.15 percent of polybutene-lhaving a molecular weight in the range of about 800.

(References on following page) References Cited UNITED STATES PATENTSPyzel 44-80 'Lieber et a1. 44--62 5 Clough et a1. 44-62 Clough et a1.4462 Howard 44--9 8 FOREIGN PATENTS 848,777 9/1960 Great Britain.993,744 6/ 1965 Great Britain.

DANIEL E. WYMAN, Primary Examiner Y. H. SMITH, Assistant Examiner US.Cl. X.R. 44-62, 80

